Merge branch 'add_link_to_fork_counter_button' into 'master'

Add link to forks pages in fork counter button

closes #14412 

![fork_link](/uploads/5afef05bc592b0cf1c90ae4d154aed87/fork_link.gif)

See merge request !3387

app/assets/stylesheets/pages/projects.scss

@@ -162,7 +162,7 @@
   margin-right: 12px;
 
   a {
-    margin: -1px !important;
+    margin: -1px;
   }
 }
 

app/views/projects/buttons/_fork.html.haml

@@ -12,7 +12,7 @@
       = link_to new_namespace_project_fork_path(@project.namespace, @project), title: "Fork project", class: 'btn has-tooltip' do
         = icon('code-fork fw')
         Fork
-      %div.count-with-arrow
+      = link_to namespace_project_forks_path(@project.namespace, @project), class: 'count-with-arrow' do
         %span.arrow
         %span.count
           = @project.forks_count